JavaScript实现横向展开二级导航菜单

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
 <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
 <title>横向伸展开来的二级导航菜单</title>
 <style type="text/css">
  .suckerdiv { }
  .suckerdiv ul { width: 120px; position: relative; }
  .suckerdiv ul li ul { left: 120px; /* Parent menu width - 1*/ position: absolute; width: 140px; /*sub menu width*/ top: 0; display: none; }
   /*All subsequent sub menu levels offset */
  .suckerdiv ul li ul li ul { left: 159px; /* Parent menu width - 1*/ }
   /* menu links style */
  .suckerdiv ul li a { display: block; color: #353302; text-decoration: none; font:12px 宋体; background: #eee; line-height:24px; padding: 0px 10px; border: 1px solid #fff; border-bottom: 0; }
  .suckerdiv ul li a:visited { color: black; }
  .suckerdiv ul li a:hover{ color: white; background-color: #97c839; }
  .suckerdiv .subfolderstyle { }
  .suckerdiv a.subfolderstyle:hover { background: #97c839 url() no-repeat center right; }
 </style>
</head>
<body>
<script type="text/javascript">
 var menuids = ["suckertree1"]
 function buildsubmenus() {
  for (var i = 0; i < menuids.length; i++) {
   var ultags = document.getElementById(menuids[i]).getElementsByTagName("ul")
   for (var t = 0; t < ultags.length; t++) {
    ultags[t].parentNode.getElementsByTagName("a")[0].className = "subfolderstyle"
    ultags[t].parentNode.onmouseover = function () {
     this.getElementsByTagName("ul")[0].style.display = "block";
     this.firstChild.style.backgroundColor = 'green';
    }
    ultags[t].parentNode.onmouseout = function () {
     this.getElementsByTagName("ul")[0].style.display = "none"
     this.firstChild.style.backgroundColor = '';
    }
   }
  }
 }
 if (window.addEventListener)
  window.addEventListener("load", buildsubmenus, false)
 else if (window.attachEvent)
  window.attachEvent("onload", buildsubmenus)
</script>
<div class="suckerdiv">
 <ul id="suckertree1">
  <li><a href="#">腾讯新闻</a></li>
  <li><a href="#">腾讯汽车</a></li>
  <li><a href="#">腾讯科技</a></li>
  <li><a href="#">腾讯手机</a>
   <ul>
    <li><a href="#">HTC</a></li>
    <li><a href="#">联想</a></li>
    <li><a href="#">华为</a></li>
    <li><a href="#">中兴</a></li>
   </ul>
  </li>
 </ul>
</div>
</body>
</html>